1. Field of the Invention
The present invention relates to an apparatus and a method for generating a three-dimensional image, and more particularly, to an apparatus and a method for converting a two-dimensional image sequence into a three-dimensional image using the motion of the two-dimensional image sequence and post-processing method during the generation of a three-dimensional image.
2. Description of the Related Art
FIG. 1 is a flowchart for describing a conventional method for generating a three-dimensional image using a modified time difference.
Sanyo Electronics Co. Ltd. has developed a method using a modified time difference (MTD) in the conventional method for generating the three-dimensional image. Referring to FIG. 1, a moved region is extracted from the two dimensional image sequence (step 100). The moving speed and direction of the extracted area are extracted (step 110). A delay direction and a delay time are determined from a previous image frame based on the moving speed and direction of a current image (step 120). Then, a determination is made as to which eye a delayed image and the current image are respectively displayed according to the determined delay direction and delay time (step 130).
FIG. 2 describes processes of determining left/right images in the method described in FIG. 1. To be more specific, FIG. 2 describes processes of determining the left/right images when a camera for capturing the images of the two-dimensional image sequence is fixed and a subject .box-solid. in an image moves. According to the conventional method using the MTD, a binocular disparity is provided to a person by showing the image time delayed in the left eye shown in FIG. 2. A binocular disparity opposite to the above-mentioned one is provided by showing an original image to the left eye and the time delayed image to the right eye when the subject .box-solid. moves to the left.
The conventional method for generating the three-dimensional image using the MTD has the following problems.
First, since an image is selected as the delayed image among previous frames based on only motion information of the original image, other depths of the respective regions of the original image are ignored. As a result, a sense of depth cannot be felt and a cubic effect can be felt in a moving subject. However, it is not possible to feel the cubic effect in a subject which barely moves such as the background of a screen.
Second, when the motion of a subject has a vertical component between the original image and the delayed image, if the three-dimensional image is generated by the conventional method using the MTD, the viewer's eyes become tired due to the visual structure of humans in which a sense of depth is obtained by a horizontal disparity.
Third, when the motion vector of a subject in the original image is very large, even if a frame is selected as the delayed image from a plurality of previous frames, the disparity of the stereo-image generated by the original image and the delayed image is beyond the limits of humans to perceive disparity.
In general, in the method for generating the three-dimensional image from the two dimensional image sequence, the two-dimensional image sequence photographed by a single eyed video camera and another image corresponding thereto are used. Here, how another image is made is important. If the quality of the made image is deteriorated, for example, the real motion of the subject in a single eyed image is not described well and the boundary of the subject is broken, a natural three-dimensional image is not generated.